Unless there's a way for us to tell you there's a kartparty going on, then the only way for you to know is to be lucky, as mm201 said.
You say you don't keep osu! turned on but is there another way to contact you? Like AIM or MSN or something? I'd happily take a few seconds to message you whenever it's going down if it's an option.
Also, knowing what times people are around may help. I'm generally around most of the evening after I get home from work, which tends to be between 6-8pm (GMT-5). Often I'm around at random on weekends too.
And if there isn't a game in progress, why not try starting one? A number of us have kartparty on our highlights now for exactly this purpose.
You say you don't keep osu! turned on but is there another way to contact you? Like AIM or MSN or something? I'd happily take a few seconds to message you whenever it's going down if it's an option.
Also, knowing what times people are around may help. I'm generally around most of the evening after I get home from work, which tends to be between 6-8pm (GMT-5). Often I'm around at random on weekends too.
And if there isn't a game in progress, why not try starting one? A number of us have kartparty on our highlights now for exactly this purpose.